Directory
Chemistry in Confined Space
Supramolecular catalysis
L. Guy, J.-P. Dutasta, collaboration A. Martinez
In collaboration with Pr. A. Martinez (ECM Marseille), we aim to develop further the project related to organocatalysis and organometallic catalysis in confined spaces. If enhancement of the catalyst robustness or its activity is expected, the main issue that will be raised by this project is the selectivity one.
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The deep active site pockets provided by the artificial catalytic cavities will induce a dramatically improvement of the substrate- chemio- regio- and stereo-selectivity. For the organocatalysis and organometallic catalysis we will focus on proton transfer (acide-base reactions) and electron transfer (oxydoreduction reactions) respectively. The closed environment induced by the cage around the active site will be particularly relevant to increase the selectivity in the transfer of such small entities. Our strategy involving the encapsulation of the active catalyst in a deep compact pocket will benefit from local skills: our team is pioneer and world leader in the chemistry of hemicryptophanes. This class of host compounds presents a remarkable feature: the possibility to achieve the endohedral functionalization of their molecular cavity. We have demonstrated that once encaged in the tight space of a hemicryptophane cage, the catalyst can display higher stability, activity or selectivity. Based on these results we aimed to explore further the high potential of this encaged catalysts by designing tailor-made confined medium nanoreactors for efficient and highly selective catalysis.
Collaboration with A. Martinez
Synthesis and chiroptical properties of new molecular cages
T. Brotin
Stereochemistry and chirality issues have been present for many years in our research activities. We will pursue these studies and develop new enantiopure cage compounds for their intrinsic interest and the development of chiroptical techniques.
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ECD and VCD spectroscopies as well as ROA (Raman Optical Activity) will be used to characterize recognition phenomena. This needs to develop new strategies for the synthesis of enantiopure supramolecular hosts, in particular cryptophanes that play a key role in the construction of enantiopure xenon-biosensors.
Synthesis of enantiopure molecular hosts for the detection/extraction of ionic species
T. Brotin
We have recently demonstrated, thanks to the use of chiroptical techniques such as ECD spectroscopy, that enantiopure cryptophanes could be used as stimuli-responsive supramolecules in solution. This feature was clearly demonstrated in the case of the detection of cationic species (cesium and thallium ions) in water at low concentration.
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The interaction between cations and cryptophanes gives rise to a very specific ECD signature that can be used to characterize the complexes. In the near future, we would like to focus on the synthesis of new cryptophanes that present higher affinity for these cations as well as large chiroptical changes upon binding. In addition, we wish to extent this work to the preparation of cryptophane molecules grafted on gold or nanoparticles for the efficient extraction of toxic metal ions from water.